3.5 Mutations

Question 1

what is a mutation?

Answer 1

a natural process that changes the DNA sequence

ex environment exposure to certain chemicals

Question 2

what is an example of a common process of a mutation that occurs in the human genome?

Answer 2

during replication of the human genome, a typo occurs every 100,000 nucleotides or so. Therefore, 120,000 typos occur each time one of our cells divides. Cells uses DNA polymerase to repair most mistakes

Question 3

what are the three types of mutations?

Answer 3

1. Neutral ( no consequences)
2. Beneficial ex they might provide benefits in a certain environment

ex Mutations protecting humans from developing atherosclerosis (a dangerous build-up of fatty material in the blood vessels)

3. Harmful

Question 4

what is the definition of point mutation?

Answer 4

when a single nucleotide base is removed from a nucleotide sequence and replaced with another base

Question 5

what is substitution mutation

Answer 5

when one or more bases in a nucleotide sequence are replaced by the same number of bases

Question 6

what is the definition of mutation inversion?

Answer 6

when a segment of DNA in a nucleotide sequence is reversed

Question 7

what is the definition of mutation insertion?

Answer 7

when one or more nucleotides are inserted into a nucleotide sequence

Question 8

where do mutations come from?
c,r,d

Answer 8

1. an error in cell division
2. if DNA polymerase makes a mistake during DNA replication

can be repaired by repair enzymes in DNA replication but not always perfectly

3. when there is damage in nucleotide sequence such as a double-strand break, damage in chemical bonds between neighboring nucleotides, damage in the chemical alteration of a nucleotide, and damage between chemical linkage of two strands

Question 9

what are some of the consequences of a mutation?
(Ssni)

Answer 9

1. Nothing

ex. a silent mutation which is a mutation that does affect the sequence of amino acids that make up a protein

2. when a single base pair substitution changes the genetic code in such a way as to produce an amino acid different from the usual amino acid
3. nonsense mutation-genetic alterations that cause premature termination of a protein. the altered protein may be inactivated partially or completely resulting in a loss or change of protein function

ex HBB gene thalassemia, a nonsense mutation would be the gene having less hemoglobin than normal

4. the insertion or deletion of nucleotides that are not in multiples of three. This disrupts the triplet reading frame of a DNA sequence. As a result, it changes the codons and corresponding amino acids after the mutation site

Question 10

what is a deletion mutation?

Answer 10

when one or more nucleotides are removed from the DNA sequence

Question 11

what is a frameshift mutation?

Answer 11

an insertion or deletion of a number of bases pairs that are not in multiples of three, the consequently disrupt the triplet reading frame of a DNA sequence